Now, if I recall correctly, the celibate priesthood is not a capital "T" tradition, it's rather a matter of discipline. I was listening to Catholic Answers a while back and heard Tim Staples say it is theoretically possible this could be changed, and priests could be allowed to marry in the future.
Ask a Catholic.com states, "Well, the celibate priesthood is in place because of the demands of the priesthood on the individual. If someday the Holy Spirit leads the Church to change it, the Church will."
Catholic Answers states, "Even within the Latin Rite, the Church has made exceptions for a number of converted married ministers to become ordained. This is known as the "pastoral provision," and it demonstrates that clerical celibacy is a discipline, not a doctrine. The doctrines of the Church are teachings that can never be reversed. On the other hand, disciplines refer to those practices (such as eating meat on Fridays) that may change over time as the Church sees fit."
So, Luther's being maligned for something that theoretically could be validated at some point in the future. As a priest, Luther's now considered by many as an adulterer for his marriage to a nun, perhaps in 2050, priests could be allowed to marry. Does that mean he'll no longer be considered an adulterer? One then has to argue his vows to the religious life continue to make him an adulterer.
On a related note, here's one I found in Martin Luther The Christian Between God and Death (Cambridge, Belknap Press, 1999) by Richard Marius. According to Marius, Erasmus initially believed the popular rumor that Cathrine Von Bora had given birth a few days after her wedding, and then commented on whether the child may in fact be the Antichrist. On page 438, Marius describes Luther knew he would be attacked for his marriage:
His forecast that his enemies would reproach him was on the mark. Then and for centuries afterward Catholic antagonists had proof that all Luther had ever wanted was sex, and since he married a former nun, it seemed he had now lived out yet another of the bawdy stories told of nuns and monks lusting for one another. His most bitter foes crowed over the marriage in monotonous fury in print. Erasmus knew of it by October and wrote to friends ironically about it. He passed on the canard that Katherine had given birth to a child a few days after the wedding (10). By March 13 he had learned that the rumor was false, although he understood (correctly) that Katherine was now pregnant. He ruminated on the 'popular legend' that the Antichrist would be born to a monk and a nun- a tale probably circulating about Luther's coming child. If that prophecy were true, he said with bitter wit, 'How many thousands of Antichrists had the world already known!'(11) He expressed the wistful hope that marriage might make Luther more gentle, but by this time he had seen Luther's vehement On the Bondage of the Will, and he had given up all hope that Luther might moderate his language.
(10) October 10, 1525; EE no. 1633; 6:197-199.
(11) March 13, 1525; EE no. 1677; 6:283-284.
EE= Opus epistolarum Des. Erasmi Roterodami, ed. Percy S. Allen et al., 12 vols. (Oxford: Oxford University Press, 1906-1958).
One may think that since Erasmus "ruminated on the popular legend" he actually took it seriously. This is hardly the case as his comment of "bitter wit" explains. It does go to show popular Catholic propaganda that circulated during the 16th century.
Phillip Schaff interprets the same facts:
[Luther's marriage] was a rich theme for slander and gossip. His enemies circulated a slander about a previous breach of the vow of chastity, and predicted that, according to a popular tradition, the ex-monk and ex-nun would give birth to Antichrist. Erasmus contradicts the slander, and remarked that if that tradition was true, there must have been many thousands of antichrists before this.3
(1526): " De conjugio Lutheri certum est, de partu maturo sponsae vanus erat rumor, nunc tamen gravida esse dicitur. Si vera est vulgi fabula Antichristum nasciturum ex monacho et monacha quemadmodum isti jactitant, quot Antichriatorum millia jam olim habet mundus? At ego sperabam fore, ut Lutherum uxor redderet magis cicurem. Verum ille praeter omnem expectationem emisit llbrum in me summa quidem cura elaboratum, sed adeo virulentum, ut hactenus in neminem scripserit hostilius."
It appears Schaff has the date wrong. The date of the letter is March 13, 1525. It is one of two surviving letters to Francois Dubois (Franciscus Sylvius).
Luther Vindicated by Charles Hastings Collette outlines the same material:
The learned Romanist, Erasmus, who was ordained a Priest in 1492, also a contemporary and opponent of Luther, gave the following testimony on this subject: "Luther's marriage is certain; the report of his wife's being so speedily brought to bed is false, but I hear she is now with child, if the common story be true, that Antichrist shall be born of a Monk and a Nun, as they pretend, how many thousands of Antichrists are there in the world already?"(3) And that Erasmus was unprejudiced, appears in his following words, viz.: " I was in hopes a wife would have made Luther a little tamer, but he, contrary to all expectations, has published a most elaborate work against me, but as virulent as any book that ever he wrote." It must be remembered that Erasmus himself had previously propagated the scandal, in a letter addressed to the President of the High Council of Holland, in 1525, on erroneous reports, spread by Luther's enemies, but which reports, as I have already shown, he was honest enough subsequently to contradict.
This would explain why
Erasmus sent word to Nicholas Everard, president of the court of Holland, that the Lutheran tragedy would end, like the quarrels of princes, in matrimony. He says, " If the common story be true, that antichrist shall be born of a monk and a nun, as they pretend, how many thousands of antichrists are there in the world already? I was in hopes that a wife would have made Luther a little tamer; but he has published a book against me, more virulent than ever." Erasmus was not well instructed in this affair, or he was too prone to give credit to the scandal which was published against Luther.